Esophageal Cancer in Iran: A Review

Esophageal cancer is the second and third most common malignancy in Iranian malesand females, respectively; killing approximately 5800 Iranians each year. Squamouscell carcinoma (SCC) is presently the most common type accounting for about 90%of all esophageal cancers in Iran. Recent studies in Iran have shown that there is a gradualincrease in the incidence of adenocarcinoma of the distal esophagus along with gastriccardia adenocarcinoma.Thirty-five years ago, the age adjusted incidence rate of esophageal SCC in thecity of Gonabad (Golestan Province, northeast Iran) and further to the east, was foundto be one of the highest rates for any single cancer that had been reported worldwide(age-adjusted rates >100/105/year). Recent studies have shown that the incidence ofSCC in Gonabad has declined to less than half of what it was in the past. This declinein the incidence of esophageal SCC parallels an improvement in the socioeconomicsituation of people living in this region. According to recent cancer registry data in Iranthere is still an obvious intracountry variability between the incidence of esophagealcancer in the south with an age standardizied rate (ASR) of 3 for males and 2 for femalesin Kerman and 43 and 36 in the northeastern province of Golestan, respectively formales and females. The reasons for the very high rate of SCC in northeastern Iran havebeen the subject of several studies during the past 35 years. According to results ofthese studies the suspected risk factors are: low intake of fruits and vegetables, drinkinghot tea, consumption of opium products and tobacco, H.pylori infection in the stomach,using unhealthy drinking water from cisterns and genetic susceptabilty. The mainsuspected mutagens are polycyclic aromatic hydrocarbons (PAH) and N-nitrosocompounds. In order to embark on a primary and secondary prevention of this fatalcancer further prospective studies are presently underway in northeastern Iran. TheGolestan esophageal cancer cohort study with an enrollment of 50,000 subjects is nowin its follow-up phase. We expect both simple and feasible evidence based preventivestrategies to be implemented in the future from the results of these studies.